It is often desirable in stage lighting applications to provide a backlighting backdrop for the scene also called a "cyclorama" or simply "cyc". Such a lighting backdrop is often effected by incandescent lights which are desirably colored. The change of color allows, for example, any desired white balance for the background.
A common color changing medium used for such backlighting is a graduated gel media. The gel is rolled between two spools, and the position of unrolling of the gel determines its color. Such a device is availible from LIGHT AND SOUND DESIGN (.TM.), Birmingham England, under the trademark of WASHLIGHT(.TM.).
Fluorescent light is ideal for large area lighting for many reasons. First of all, fluorescent produce their lights along a relative long line. Fluorescent uniformly produces its lighting effect along that long line. This compares to many other lights which are essentially point sources. However, the fluorescent lights often dim poorly.